1. Field of the Invention
The invention concerns a process for manufacturing a curved part made of composite material, as well as a device to be used in the manufacture of such a curved part of composite material that can be used to implement the process according to the invention. The invention particularly concerns parts made of stratified composite material comprising layers of reinforcing fibers immersed in a heat curable polymer resin.
The invention will be applicable in the field of aeronautics for the manufacture of relatively thick aircraft parts, i.e. in the range of 10 to 25 mm, such as angle brackets, spars, wing surface and fuselage components, etc.
2. Description of the Related Art
At present, in order to make a part with a local radius of curvature from a composite material, a known process entails draping fiber strips of a composite material directly onto a molding preform with the desired radius of curvature, so as to obtain the desired curved part when the substance cures. However, this manufacturing method is unsatisfactory, primarily from the production perspective.
Another known heat bending system is used to make aircraft angle brackets and the folded edge of upper panels. Nonetheless, this bending device cannot be used to obtain stretched fibers in each section of the part after polymerization, and notably with regard to the radius of curvature. In the first place, bending causes crimping of compressed fibers in the internal radius of a part and in the second place, autoclave pressure forming does not always suffice for offsetting insufficient fiber lengths due to shrinkage of the part during polymerization.
Thus, ripples in the fibers can be observed in the internal radius of the finished part corresponding to excessive fiber length resulting from crimping of creases in compressed composite materials. In addition, the final part may display porosity due to improper compaction by autoclave pressure, especially in the radius area, due to insufficient fiber lengths during the shrinking process.